#函数链式使用与嵌套

# def judge(z):
#     if z % 2 == 0:
#         return True
#     else:
#         return False
#
# def add(x,y):
#         return x + y
#
# x = 3
# y = 4
# print(judge(add(x,y)))

# def a():
#     print('a')
#
# def b():
#     a()
#     print('b')
#
# def c():
#     b()
#     print('c')
#
# def d():
#     c()
#     print('d')
#
# d()

# # 递归
# def fibonacci(n):
#     if n < 2:
#         return n
#     return fibonacci(n-1) + fibonacci(n-2)
#
# for i in range(10):
#     print(fibonacci(i))